Funding for this research was provided by:
Council for Scientific and Industrial Research, South Africa (31/014(2764)/2018-EMR-1)
Received: 10 April 2020
Accepted: 7 October 2020
First Online: 18 January 2021
Compliance with Ethical Standards
: All authors have seen and approved the manuscript being submitted. Hence, on behalf of all authors, the corresponding author states that there is no conflict of interest.